Sent QUIC "PING" frames when a stream is open and the connection

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index 99d841f03bb62e33e584b700de994692756d4403..115345db97447a12660639abf93ffa25bb51bd07 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -129,6 +129,21 @@ class TimeoutAlarm : public QuicAlarm::Delegate {
   QuicConnection* connection_;
 };
 
+class PingAlarm : public QuicAlarm::Delegate {
+ public:
+  explicit PingAlarm(QuicConnection* connection)
+      : connection_(connection) {
+  }
+
+  virtual QuicTime OnAlarm() override {
+    connection_->SendPing();
+    return QuicTime::Zero();
+  }
+
+ private:
+  QuicConnection* connection_;
+};

[jar (doing other things), 2014/04/18 21:57:13]

nit: NO_DEFAULT_COPY_AND_ASSIGN

[Ryan Hamilton, 2014/04/19 13:55:59]

Done.

+
 QuicConnection::PacketType GetPacketType(
     const RetransmittableFrames* retransmittable_frames) {
   if (!retransmittable_frames) {
@@ -191,6 +206,7 @@ QuicConnection::QuicConnection(QuicConnectionId connection_id,
       send_alarm_(helper->CreateAlarm(new SendAlarm(this))),
       resume_writes_alarm_(helper->CreateAlarm(new SendAlarm(this))),
       timeout_alarm_(helper->CreateAlarm(new TimeoutAlarm(this))),
+      ping_alarm_(helper->CreateAlarm(new PingAlarm(this))),
       debug_visitor_(NULL),
       packet_creator_(connection_id_, &framer_, random_generator_, is_server),
       packet_generator_(this, NULL, &packet_creator_),
@@ -1058,6 +1074,7 @@ void QuicConnection::ProcessUdpPacket(const IPEndPoint& self_address,
   MaybeProcessUndecryptablePackets();
   MaybeProcessRevivedPacket();
   MaybeSendInResponseToPacket();
+  SetPingAlarm();
 }
 
 void QuicConnection::OnCanWrite() {
@@ -1406,6 +1423,7 @@ bool QuicConnection::OnPacketSent(WriteResult result) {
   QuicTime now = clock_->Now();
   if (transmission_type == NOT_RETRANSMISSION) {
     time_of_last_sent_new_packet_ = now;
+    SetPingAlarm();

[jar (doing other things), 2014/04/18 21:57:13]

Why don't we always set this? Why do we care if it is a retransmission?

[Ryan Hamilton, 2014/04/19 13:55:59]

Done. I was keeping it in sync with the timeout alarm, which is based on the
time_of_last_sent_new_packet_ member. But as you point out, we don't care about
that for the purposes of the ping alarm. As a result, I've also change the
SetPingAlarm method to set based on Now().

   }
   DVLOG(1) << ENDPOINT << "time of last sent packet: "
            << now.ToDebuggingValue();
@@ -1482,6 +1500,22 @@ void QuicConnection::UpdateStopWaiting(QuicStopWaitingFrame* stop_waiting) {
       stop_waiting->least_unacked - 1);
 }
 
+void QuicConnection::SendPing() {
+  if (version() <= QUIC_VERSION_17) {
+    IOVector data;
+    char c_data[] = "C";
+    data.Append(c_data, 1);
+    QuicConsumedData consumed_data =
+        packet_generator_.ConsumeData(kCryptoStreamId, data, 0, false, NULL);
+    if (consumed_data.bytes_consumed == 0) {
+      DLOG(ERROR) << "Unable to send ping!?";
+    }
+  } else {
+    //packet_generator_.AddControlFrame(QuicFrame(new QuicPingFrame));
+  }
+  SetPingAlarm();

[jar (doing other things), 2014/04/18 21:57:13]

Do we don't need to set it again? Shouldn't it should be set by the write, and
by the read of the responsive ack.

[Ryan Hamilton, 2014/04/19 13:55:59]

Interesting! Yes, good point, the send of the PING should reset the alarm.

+}
+
 void QuicConnection::SendAck() {
   ack_alarm_->Cancel();
   stop_waiting_count_ = 0;
@@ -1802,6 +1836,22 @@ bool QuicConnection::CheckForTimeout() {
   return false;
 }
 
+void QuicConnection::SetPingAlarm() {
+  if (is_server_) {
+    // Only clients send pings.
+    return;
+  }
+  ping_alarm_->Cancel();
+  if (!visitor_->HasOpenStreams()) {
+    // Don't send a ping unless there are open streams.
+    return;
+  }
+  QuicTime time_of_last_packet = max(time_of_last_received_packet_,
+                                     time_of_last_sent_new_packet_);
+  QuicTime::Delta ping_timeout = idle_network_timeout_.Multiply(0.5);
+  ping_alarm_->Set(time_of_last_packet.Add(ping_timeout));
+}
+
 QuicConnection::ScopedPacketBundler::ScopedPacketBundler(
     QuicConnection* connection,
     AckBundling send_ack)